[MrRage]

I am going to replace my 7/8" lead screw in my milling machine and was wondering which option made the most sense.

1) Replace with a 3/4" leadscrew. At $250 this options is the cheapest and would require less work to make operate than option 3, but option 2 is still simpler. Only drawback is that this screw is 15% smaller, so there would be 15% more force acting on the drive nut.

2) Replace with an identical 7/8" leadscrew. This option ties, or possibly beats option 3 in price. I've been quoted anywhere from $750-1000 for a precision ground replacement. This would be a plug-n-play solution so no modifications would need to be made.

3) Replace with a 1" leadscrew. This option is about 13" larger and in turn stronger than the stock screw, however the castings would have to be modified to accommodate for the larger nut. The place where the nut connects with the casting will have to be machined down to reassess the nut enough into the casting to allow the controls to be mounted correctly. The stock material cost is closer to $350, not including the cost of having the casting machined to accommodate for the differences.

So there you have it, my 3 options. I wanted to keep this rebuild cost effective. The 3/4" sound promising but I'm not sure if in the long run this is the best choice.

[ViperTX]

I think you have to consider the size of the ballnut...I'm thinking that you will end up with a 3/4 inch ballscrew.....oops.....you're not going with a ballscrew....okay then do a direct replacement.